Extraction and preconcentration of organophosphorus pesticides from water samples and fruit juices utilizing hydroxyapatite/Fe3O4 nanocomposite

In this study, we demonstrate the application of newly developed magnetic potassium substituted hydroxyapatite (KHA/Fe3O4) for the extraction of organophosphorus pesticides (OPPs) from water samples. Nanoparticles of KHA were synthesized through an easy alkoxide-based sol-gel technique. The structure of nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analysis, and energy dispersive X-ray analysis (EDXA). The OPPs were analyzed by gas chromatography-flame ionization detector (GC-FID). Variables affecting the performance of both extraction steps such as pH of the water sample, the sorbent amount, the desorption conditions, and the extraction time solvent were studied and optimized. Under optimum conditions, good linearity was achieved for all analytes in the 0.1-200 ng mL−1 concentration range. The limits of detection (at an S/N ratio of 3) are between 0.03 and 0.22 ng mL−1. The intra-day (n = 5) and inter-day (n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 5.2-9.1% and 5.6-9.0%, respectively. The recoveries of OPPs from spiked real water samples and fruit juices are between 89.0 and 99.7%, with relative standard deviations between 5.5 and 10.8%.